dont give the title to the people till the check clears, if there giving you a check!
Don't give them the boat either. Go to the bank with them and cash your check and then hand it over.
I think the best way to get the most out of the boat is to clean it up and make sure everything is working. Then make it as water ready as possible. Throw in a some life jackets, anchor, minnow bucket and even a couple of fishing rods if you have them. Don't misrepresent anything. If it does have a defect disclose it, and if possible, what it $$$ would take to get it fixed. Some good fishing stories helps too.